Bending it the right way: How LG and Samsung curved their phones differently

Despite advances in display tech, there's still one other big piece to curve.

In Korea, the rivalry between LG and Samsung is deep and fierce. The conglomerates clash in nearly every market, and their competitiveness often puts them in lockstep, even as they take surprising turns in product design. The latest fad is the move to curved displays on phones, and recent revelations show that there isn't yet industry consensus on how best to curve a phone.

The thing that often goes unnoticed about consumer tech fads like the curved phones we're seeing today (think 3D phones, giant phones, thin phones, phones with keyboards, and tablets with phones inside) is the amount of technical achievement required of the engineers that are behind them. The efforts to produce small 3D displays and cameras were driven by advances in image sensor processors and parallax screens. The thin phone craze was driven by shifts in the industrial design of phones and manufacturing techniques.

For the curved phone movement, the focus was initially on the development of flexible displays. The two biggest players in flexible display technology, LG and Samsung, have been demonstrating the potential of this tech for a long time. But screens aren't the biggest limiting factor in phone design, though. Nor is it cameras or silicon. It's the batteries.

Batteries are deceptively complicated. The chemical compositions of modern lithium-ion batteries are closely guarded secrets, and though they look like simple slabs of energy, their development consumes millions of research dollars annually. As thinner batteries were developed, the goal became to maximize their potential by building larger devices and devoting more area to the battery inside. But without any radical advances in the actual chemistry of the batteries, the only way to provide more charge is to increase the volume of the battery inside.

The Samsung Galaxy Note 3 has a rather large 3,200mAh battery, but that's to be expected for a phone of this size. To turn the Note 3 into the recently announced Galaxy Round, Samsung needed to do a little trimming inside. The curved display limits the width of the flat components that can fit into the curved body. The phone's silicon lives on plastic boards that are easy to reshape and reposition. Displays recently developed their own curve, and bodies and subframes can be shaped to order. Really, it's just the battery that has been resolute in its flatness so far.

The 2,800 mAh battery inside the Galaxy Round shouldn't leave it struggling to get through the day, but it is a sizable loss compared to the Note 3. In order to fit the curved body, the battery was made to be quite long and narrow. The flatness of the battery also determined the direction of the phone's curve. Curving the phone along its long axis would require either two smaller batteries, one on either side of the arc, or making do with one, much smaller battery.

An unboxing of the Galaxy Round. Note the shape of the battery. Source:UNDERkg

Then there's LG's upcoming G Flex. The images and details are just leaking out, but the one clear fact is that the phone curves longitudinally. Last week, LG fired a one-two punch, announcing its flexible displays in one press release and then publishing a release on Korea Newswire about the mass production of their curved battery technology. The technique involves separating the cathode and anode components of the battery with a flexible membrane, while wrapping the whole package in another similar membrane. From there, the flexible cells can be stacked and shaped as necessary or rolled into a cylinder for applications in wearables. The membrane layers decrease the overall density of the cells, so there is a capacity penalty paid, but the limitations on shape are almost obliterated.

Samsung is working on its own curved battery solutions, and earlier this year it announced its intention to produce "slightly curved" batteries by the end of the year. Where they are in that process is unclear. For now, LG's successes free them to build a phone with a longitudinal curve that should conform well with the face.

We still don't know what the real world value of the curved phone will be, nor do we know whether it will be a sales success. There weren't many tech pundits that trumpeted the arrival of the original Galaxy Note, yet here we are, 38 million units later. For better or worse, from screens to batteries, many innovations in design are driven by advances in the core technologies that shape our devices. We're just thankful to be able to watch it happen.

I realize this is Soviet Union style thinking but damn it, I don't want new curved phones that everyone who can afford one has to now/eventually buy because... curved phones! Can't we somehow as a species figure out some kind of a system where you would put those rare minerals, resources and energy towards actually useful research, spaceflight or sustainability?

I don't really understand what makes this technology superior in any way. So far it just looks like a showroom gimmick to entice people to buy one phone over another.

Form factor is a very important aspect of a phone. This LG looks like it might be the most comfortable phone to hold to your ear, but it doesn't like it would be very comfortable in my front pocket. It will probably do well with people that keep their phone in the bag or purse. The Samsung looks like the most comfortable phone to have in your pocket. If I got to choose between flat and the Samsung curvature, with all else being equal, I'd pick the curved version.

With only two flat edges to the phone you could set it screen side down on a flat surface without the screen making contact. A dropped phone that ends up butter side down (ZOOKS!) could possibly avoid screen damage. Though I am curious about the physical properties of curved glass versus flat. I didn't think Corning's willow glass was commercially available yet. Does anyone know what sort of glass they are looking to use in these phones?

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What HTC? What are you talking about? Also, how does the phone being curved make it less likely to get scratched?

I don't really understand what makes this technology superior in any way. So far it just looks like a showroom gimmick to entice people to buy one phone over another.

Form factor is a very important aspect of a phone. This LG looks like it might be the most comfortable phone to hold to your ear, but it doesn't like it would be very comfortable in my front pocket. It will probably do well with people that keep their phone in the bag or purse. The Samsung looks like the most comfortable phone to have in your pocket. If I got to choose between flat and the Samsung curvature, with all else being equal, I'd pick the curved version.

It's a fair point. So what we really need (until we get dynamically flexible phones) is a phone that's curved along a somewhat diagonal axis such that for the pocket people it fits perfectly to the curvature of their thigh!

Personally my phone lives in my purse and I'm not over enthused over how well (or not) a curved phone is going to fit in there, either. But I love the ergonomics of the LG... or at least my assumption of the ergonomics of the LG At the same time, since I usually have my phone on my desk screen-side up, I'm sort of wondering how that will generally go with the LG.

Exactly how is a phone with a keyboard a consumer tech fad? They may not be a large part of the market, but they've endured long enough to show that they're not a novelty. It's the reason I have a Droid 4, and it sold well enough that I know I'm not alone.

We still don't know what the real world value of the curved phone will be,

The obvious answer is scratch resistance.

Less travel distance for your thumb, too.

Upward curved surface means the display is about the same size was a wider display but your thumb can go from one side to the other a fraction faster or with less reach.

Also, our hands evolved to grip round objects (branches and such), so to hold a rounded phone is probably more comfortable.

Ease of use was the first thing I thought of when I saw the Galaxy Round. My brain was thinking "same thumb reach as the S4, but with the larger Note 3 display".

A curved phone will probably be nice to hold in your hand and may sit nicely in pockets.I remember the first time I held an iPhone 4. It had square edges on the metal frame and more square edges on the glass. It was crying out for a smooth protective case.

That site is about projector-sized screens. Unless you are holding the phone 3 inches in front of you face, the difference in FOV angle caused by the curve is going to be completely negligible. To drive this home, imagine changing that image by moving the flat screen down to the bottom of the curve instead of the top; now the flat screen has a wider FOV. Since the position of the phone in your hand is dictated by the edges of the phone, and not the center, that is the more accurate comparison anyway.

I don't understand why people would want a curved screen. Eventually, sure, I can see use cases, but not for this kind of curved screen.

Absolutely! With my head having perfectly flat sides, a flat phone fits me best. Only weirdos with deformed, rounded heads would want a phone that fits them.

The LG curve works well for voice calls but works poorly for every other activity you do on a phablet (particularly typing...with the bottom edge perpendicular to you for typing, the top of the screen is going to be curved toward your chest). Thing is, if ergonomics for voice calls were a higher priority for you than tablet-like functionality, you probably wouldn't be looking at phablets to begin with.

While I'm definitely not sold on the Samsung Round, it's curvature makes a bit more sense to me (my phone spends a lot of time in a front pants pocket, and a curve would help it fit more naturally, plus it helps your thumb reach both edges of the phone while using it as a phablet).

That site is about projector-sized screens. Unless you are holding the phone 3 inches in front of you face, the difference in FOV angle caused by the curve is going to be completely negligible. To drive this home, imagine changing that image by moving the flat screen down to the bottom of the curve instead of the top; now the flat screen has a wider FOV. Since the position of the phone in your hand is dictated by the edges of the phone, and not the center, that is the more accurate comparison anyway.

LG's phone can easily occupy 30° of HFOV. That's not that far away from what a projector-sized screen would occupy (~40°). In that case, FOV increase is 2.35% (if equidistant - it isn't, for LG it's equidistant when it occupies 11° (from 700mm)). Curve will feel like heaven on PC monitors (anything larger than a phone really) and cylindrical projections. Higher FOV with lower price, edge resolution doesn't go to waste thanks to rectilinear type of projection - heaven.

I realize this is Soviet Union style thinking but damn it, I don't want new curved phones that everyone who can afford one has to now/eventually buy because... curved phones! Can't we somehow as a species figure out some kind of a system where you would put those rare minerals, resources and energy towards actually useful research, spaceflight or sustainability?

My iPhone 3GS that I possessed for a time, had a curved back that was comfortable to hold. The curved phones shown and described in this article look comfortable to handle. I hope they would incorporate wireless charging; preferably the QI wireless standard.

Elements of cell phone technology may make it into spaceflight, if it has not already.

I think Samsung have chosen the correct curvature, it will fit better in your pocket where it stays 90% of the time.

I don't agree with that. The LG's longitudinal curve seems far more practical. It will still curve nicely over your thigh (especially when sitting down), it helps bring the microphone closer to your mouth, and it looks more like the curve one would expect from a telephone handset.

What HTC? What are you talking about? Also, how does the phone being curved make it less likely to get scratched?

Sorry, I meant the LG photographed in the article. I'll edit my comment.

Having a convex curve means the screen is less likely to touch stuff. Eg if you drop your phone and it slides along the concrete, only the edge will get scratched.

I've dropped my iPhone(s) onto concrete or asphalt 20 or 30 times in the last ~4 years. Also, one time the phone landed *exactly* face down instead of a corner hitting first, meaning the screen took the impact instead of the tiny plastic/aluminium (depending on the model of iPhone) ridge around the glass - which meant the glass shattered instead of just being scratched.

With a curved screen a phone abused the way I abuse mine would have less scratches and it wouldn't have shattered the only time I've ever had one shatter.

The iPhone 3GS that I had a few years ago drove me insane with its curved back. It was fine in the front pants pocket and when holding it, but at work it usually sat on its back on my desk, rocking back and forth every time I poked at the screen to interact with it. Hold STILL, dammit! The flat back on the iPhone 4/4S was one of the most satisfying changes Apple made on their newer phones if you ask me.

We still don't know what the real world value of the curved phone will be,

The obvious answer is scratch resistance.

Less travel distance for your thumb, too.

Upward curved surface means the display is about the same size was a wider display but your thumb can go from one side to the other a fraction faster or with less reach.

Also, our hands evolved to grip round objects (branches and such), so to hold a rounded phone is probably more comfortable.

going from a recently stolen nexus s4g (curved) to the GS4 my biggest gripe is the damn thumb travel... i alternate feeling lazy for not wanting to hyper extend my thumb...to cursing the designers for making me have to.

in other news... idk why reviewers tend to have low iqs(see LED TV) but these are not "flexible" displays. the tech behind them was...but then it was cast into a permanent curve making them flexed or curved... the dude in the video seems to have a lot of trouble remembering the difference and a lot of headlines i have seen do the same.